The ball screws are used in the movable platforms of high-precision machines and are important parts for precision industry.
The conventional ball screw 90 is rotated to linearly transmit a nut 910 mounted to the ball screw 90 and heat is generated during the transmission due to friction between the nut 910 and the ball screw 90. The maximum temperature is located at the center of the nut 90 wherein the balls 952 are in contact with, the maximum temperature area is designated as the max-temp area 910A. As show in FIG. 13, the temperature gradually drops from the max-temp area 910A toward two ends of the nut 910, wherein the levels of the temperature are shown by the density of the bars and the max-temp area 910A is shown by the highest density of the bars.
When the temperature of the nut 910 is increased, the heat affects the length of the nut 910 so that it cannot be precisely positioned and the precision of positioning of the system fails. It is obvious that the temperature affects the precision and the positioning so that the nut 901 needs to be reduced.
The present invention intends to provide a nut for ball screws and the nut improves the shortcomings of the conventional nuts.